Add .samignore for excludes in python_pip_workfow

aws_lambda_builders/workflows/python_pip/workflow.py

@@ -1,6 +1,7 @@
 """
 Python PIP Workflow
 """
+import pathlib
 from aws_lambda_builders.workflow import BaseWorkflow, Capability
 from aws_lambda_builders.actions import CopySourceAction
 from aws_lambda_builders.workflows.python_pip.validator import PythonRuntimeValidator
@@ -16,7 +17,7 @@ class PythonPipWorkflow(BaseWorkflow):
 
     # Common source files to exclude from build artifacts output
     # Trimmed version of https://github.com/github/gitignore/blob/master/Python.gitignore
-    EXCLUDED_FILES = (
+    _DEFAULT_EXCLUDED_FILES = (
         ".aws-sam",
         ".chalice",
         ".git",
@@ -65,8 +66,19 @@ def __init__(self, source_dir, artifacts_dir, scratch_dir, manifest_path, runtim
 
         self.actions = [
             PythonPipBuildAction(artifacts_dir, scratch_dir, manifest_path, runtime, binaries=self.binaries),
-            CopySourceAction(source_dir, artifacts_dir, excludes=self.EXCLUDED_FILES),
+            CopySourceAction(source_dir, artifacts_dir, excludes=self.excluded_files),
         ]
 
+    @property
+    def excluded_files(self):
+        """
+        Use .samignore falling back to default exclude files
+        """
+        sam_ignore = pathlib.Path("./.samignore")
+        if sam_ignore.exists():
+            return sam_ignore.read_text().splitlines()
+        else:
+            return self._DEFAULT_EXCLUDED_FILES
+
     def get_validators(self):
         return [PythonRuntimeValidator(runtime=self.runtime)]

tests/unit/workflows/python_pip/test_workflow.py

@@ -1,3 +1,6 @@
+import pytest
+import pathlib
+import mock
 from unittest import TestCase
 
 from aws_lambda_builders.actions import CopySourceAction
@@ -17,3 +20,28 @@ def test_workflow_sets_up_actions(self):
     def test_workflow_validator(self):
         for validator in self.workflow.get_validators():
             self.assertTrue(isinstance(validator, PythonRuntimeValidator))
+
+
+@pytest.mark.parametrize("use_samignore", (False, False))
+def test_use_sam_ignore(tmpdir, use_samignore):
+    """
+    Verify if there is a `.samignore` workflow will give that preference
+    over the default files to exclude.
+    """
+
+    sam_ignore = pathlib.Path("{tmpdir}/.samignore".format(tmpdir=tmpdir))
+
+    if use_samignore:
+        sam_ignore.write_text("foo*.txt\n*-bar.so\n")
+
+    pathlib.Path = mock.MagicMock(return_value=sam_ignore)
+    mock.patch.object(sam_ignore, "exists", return_value=use_samignore)
+
+    _workflow = PythonPipWorkflow("source", "artifacts", "scratch_dir", "manifest", runtime="python3.7")
+
+    pathlib.Path.assert_called_once_with("./.samignore")
+
+    if use_samignore:
+        assert _workflow.excluded_files == ["foo*.txt", "*-bar.so"]
+    else:
+        assert _workflow.excluded_files == _workflow._DEFAULT_EXCLUDED_FILES